From: William Lallemand <wlallemand@haproxy.com>
Date: Tue, 30 Jun 2026 13:14:53 +0000 (+0000)
Subject: MEDIUM: ssl: add FIPS TLS 1.3 ciphersuite check for AWS-LC
X-Git-Url: http://git.kaiwu.me/%7Bsubstring-before(@doc,%20'.xml')%7D.html?a=commitdiff_plain;h=29f5126317ebc3f48575f98b69143060baa2cf05;p=haproxy.git

MEDIUM: ssl: add FIPS TLS 1.3 ciphersuite check for AWS-LC

AWS-LC does not expose TLS 1.3 ciphersuites set via SSL_CTX_set_ciphersuites()
through SSL_CTX_get_ciphers(), so the existing NID-based cipher check in
ssl_fips_check_ciphers() cannot catch non-FIPS TLS 1.3 suites.  This is
further compounded by a defect in the AWS-LC-FIPS 3.x branch where TLS 1.3
ciphers are missing from SSL_get_ciphers() entirely (fixed in
https://github.com/aws/aws-lc/pull/2092), making any SSL_CTX-based
inspection unreliable across versions.

Add ssl_fips_check_ciphersuites() which validates the ciphersuite string
directly against a FIPS-approved allowlist (TLS_AES_128_GCM_SHA256 and
TLS_AES_256_GCM_SHA384).  A NULL string is silently accepted since the
global defaults were already overwritten with FIPS values at init time.

The new check is called right after SSL_CTX_set_ciphersuites() in both
the bind (ssl_sock_prepare_ctx) and server (ssl_sock_prepare_srv_ssl_ctx)
configuration paths.
---

diff --git a/include/haproxy/fips.h b/include/haproxy/fips.h
index 031adb380..02198fede 100644
--- a/include/haproxy/fips.h
+++ b/include/haproxy/fips.h
@@ -9,6 +9,7 @@
 
 #if defined(OPENSSL_IS_AWSLC)
 int ssl_fips_check_ciphers(SSL_CTX *ctx, const enum obj_type *obj, char **err);
+int ssl_fips_check_ciphersuites(const char *ciphersuites, const enum obj_type *obj, char **err);
 int ssl_fips_check_version(int min_ver, const enum obj_type *obj);
 #endif
 
diff --git a/src/fips.c b/src/fips.c
index 5c4d6599c..fc7c994d1 100644
--- a/src/fips.c
+++ b/src/fips.c
@@ -20,6 +20,15 @@ static const int fips_approved_cipher_nids[] = {
 	NID_undef
 };
 
+/* FIPS-approved TLS 1.3 ciphersuite names.  NULL terminates the list.
+ * TLS_AES_128_CCM_SHA256 is FIPS-approved but not implemented by AWS-LC. */
+static const char *fips_approved_ciphersuites[] = {
+	"TLS_AES_128_GCM_SHA256",
+	"TLS_AES_256_GCM_SHA384",
+	"TLS_AES_128_CCM_SHA256",
+	NULL
+};
+
 /* Fill display fields from <obj> for use in error messages. */
 static void fips_obj_info(const enum obj_type *obj,
                           const char **proxy_name, const char **type_str,
@@ -52,6 +61,48 @@ static void fips_obj_info(const enum obj_type *obj,
 	}
 }
 
+/* Check that the TLS 1.3 ciphersuite list <ciphersuites> is FIPS-compliant. */
+int ssl_fips_check_ciphersuites(const char *ciphersuites, const enum obj_type *obj, char **err)
+{
+	const char *proxy_name, *type_str, *obj_name, *file;
+	const char *p, *end;
+	char *list = NULL;
+	int i, line;
+	size_t len;
+
+	if (!FIPS_mode() || !ciphersuites)
+		return 0;
+
+	p = ciphersuites;
+	while (p && *p) {
+		end = strchr(p, ':');
+		len = end ? (size_t)(end - p) : strlen(p);
+
+		for (i = 0; fips_approved_ciphersuites[i]; i++) {
+			if (strlen(fips_approved_ciphersuites[i]) == len &&
+			    strncmp(p, fips_approved_ciphersuites[i], len) == 0)
+				goto next;
+		}
+		memprintf(&list, "%s%s'%.*s'", list ? list : "",
+		          list ? ", " : "", (int)len, p);
+	next:
+		p = end ? end + 1 : NULL;
+	}
+
+	if (list) {
+		fips_obj_info(obj, &proxy_name, &type_str, &obj_name, &file, &line);
+		if (file)
+			memprintf(err, "%s[%s:%d] %s '%s/%s': FIPS mode active but non-FIPS ciphersuite(s) configured: %s.\n",
+			          (err && *err) ? *err : "", file, line, type_str, proxy_name, obj_name, list);
+		else
+			memprintf(err, "%s%s '%s/%s': FIPS mode active but non-FIPS ciphersuite(s) configured: %s.\n",
+			          (err && *err) ? *err : "", type_str, proxy_name, obj_name, list);
+		free(list);
+		return ERR_ALERT | ERR_ABORT | ERR_FATAL;
+	}
+	return 0;
+}
+
 /* Check that the TLS 1.2 cipher list configured on <ctx> is FIPS-compliant. */
 int ssl_fips_check_ciphers(SSL_CTX *ctx, const enum obj_type *obj, char **err)
 {
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index 0fb4b6951..dddf8c164 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -4730,6 +4730,10 @@ static int ssl_sock_prepare_ctx(struct bind_conf *bind_conf, struct ssl_bind_con
 		          err && *err ? *err : "", curproxy->id, conf_ciphersuites, bind_conf->arg, bind_conf->file, bind_conf->line);
 		cfgerr |= ERR_ALERT | ERR_FATAL;
 	}
+#if defined(OPENSSL_IS_AWSLC)
+	cfgerr |= ssl_fips_check_ciphersuites(conf_ciphersuites,
+	                                      &LIST_ELEM(bind_conf->listeners.n, struct listener *, by_bind)->obj_type, err);
+#endif
 #endif
 
 #if defined(OPENSSL_IS_AWSLC)
@@ -5282,6 +5286,13 @@ static int ssl_sock_prepare_srv_ssl_ctx(const struct server *srv, SSL_CTX *ctx)
 			 srv->ssl_ctx.ciphersuites);
 		cfgerr++;
 	}
+#if defined(OPENSSL_IS_AWSLC)
+	if (ssl_fips_check_ciphersuites(srv->ssl_ctx.ciphersuites, &srv->obj_type, &err)) {
+		ha_alert("%s", err);
+		ha_free(&err);
+		cfgerr++;
+	}
+#endif
 #endif
 
 #if defined(OPENSSL_IS_AWSLC)